Intraperitoneally injected cultured mast cells suppress recruitment and differentiation of bone marrow-derived mast cell precursors in the peritoneal cavity of W/Wv mice.

Bone marrow-derived mast cell precursors form large mast cell colonies in methylcellulose and are designated as L-CFU-Mast. The effect of differentiated mast cells on recruitment and differentiation of L-CFU-Mast was investigated by using genetically mast cell-deficient WBB6F1-W/Wv mice. Giant granules of C57BL/6-bgJ/bgJ (Chediak-Higashi syndrome) mice were used as a marker to identify the origin of L-CFU-Mast and differentiated mast cells. Practically no L-CFU-Mast are present in the peritoneal cavity of WBB6F1-W/Wv mice. When bone marrow cells of WBB6F1(-)+/+ mice were i.v. injected, the concentration of +/+(-)type L-CFU-Mast increased in the peritoneal cavity of WBB6F1-W/Wv mice and became several times greater than that of nontreated WBB6F1(-)+/+ mice. This increase of L-CFU-Mast was suppressed by a prior i.p. injection of bgJ/bgJ-type cultured mast cells. The differentiation of the +/+(-)type L-CFU-Mast to morphologically identifiable mast cells was also suppressed by the i.p. injection of bgJ/bgJ-type cultured mast cells. The present results suggest that the suppression of recruitment and differentiation of L-CFU-Mast is a physiological function of differentiated mast cells.